Fungicidal compositions and method of controlling plant fungi

ABSTRACT

Mixtures of certain triazole fungicides (component I) and 4,6-dimethyl-N-phenyl-2-pyrimidinamine (component II) achieve synergistically enhanced activity against fungus infestation. Components I and II can also be applied to plant crops individually, one immediately after the other.

This is a division of application Ser. No. 08/642,232, filed May 2,1996, U.S. Pat. No. 5,663,176, which is a division of Ser. No.08/437,730, filed May 9, 1995, now U.S. Pat. No. 5,538,979, which is adivision of Ser. No. 08/300,499, filed Sep. 2, 1994, now U.S. Pat. No.5,447,935, which is a division of Ser. No. 08/166,780, filed Dec. 14,1993, now U.S. Pat. No.5,373,013, which is a division of Ser. No.08/016,365, filed Feb. 11, 1993, abandoned.

The present invention relates to fungicidal two-component mixtureshaving synergistically enhanced action and to methods for theapplication of such mixtures in crop protection.

Component I is an ergosterol-biosynthesis inhibitor of the triazoleseries, or a salt or metal complex thereof, selected from

A) 1-2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl!-1H-1,2,4-triazole,trade name propiconazol, (reference: GB 1 522 657);

B) 1-{2- 2-chloro-4-(4-chlorophenoxy)phenyl!-4-methyl-1,3-dioxolan-2-ylmethyl}-1H-1,2,4-triazole, trade namedifenoconazol, (reference: GB 2 098 607);

C) α-2-(4-chlorophenyl)ethyl!-α-(1,1-dimethylethyl)-1H-1,2,4-triazol-1-ethanol,trade name tebuconazol, (reference: EP-A-40 345);

D) 1-(4-chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)-butan-2-ol,trade name triadimenol, (reference: DE-OS 23 24 010);

E) 1-3-(2-chlorophenyl)-2-(4-fluorophenyl)oxiran-2-ylmethyl!-1H-1,2,4-triazole,code name BAS-480-F, (reference EP-A-196 038);

F) α-(4-chlorophenyl)-α-(1-cyclopropylethyl)-1H-1,2,4-triazol-1-ethanol,trade name cyproconazol (reference: U.S. Pat. No. 4,664,696);

G)4-(4-chlorophenyl)-2-phenyl-2-(1,2,4-triazol-1-ylmethyl)butyronitrile,proposed trade name fenbuconazol (reference: EP-A-251 775);

H) α-(2-fluorophenyl)-α-(4-fluorophenyl)-1H-1,2,4-triazol-1-ethanol,trade name flutriafol (reference: EP-A-15 756);

J) α-butyl-α-(2,4-dichlorophenyl)-1H-1,2,4-triazol-1-ethanol, trade namehexaconazol (reference: GB-2 119 653); and

K) 1- { bis(4-fluorophenyl)methylsilyl!methyl}-1H-1,2,4-triazole, tradename flusilazol (reference: U.S. Pat. No. 4,510,136).

Component II is the 2-anilinopyrimidine of the formula ##STR1##

4,6-dimethyl-N-phenyl-2-pyrimidinamine, proposed trade namepyrimethanil, or a salt or metal complex thereof (reference: DD 151404).

Of the acids that can be used in the preparation of salts of formula Ior II there may be mentioned:

hydrohalic acid, such as hydrofluoric acid, hydrochloric acid,hydrobromic acid or hydriodic acid, and sulfuric acid, phosphoric acid,nitric acid and organic acids, such as acetic acid, trifluoroaceticacid, trichloroacetic acid, propionic acid, glycolic acid, thiocyanicacid, lactic acid, succinic acid, citric acid, benzoic acid, cinnamicacid, oxalic acid, formic acid, benzenesulfonic acid, p-toluenesulfonicacid, methanesulfonic acid, salicylic acid, p-aminosalicylic acid,2-phenoxybenzoic acid, 2-acetoxybenzoic acid or1,2-naphthalenedisulfonic acid.

The term "salts" also includes metal complexes of the two basiccomponents I and II. It is possible for only one of the components or,alternatively, for both components independently to be in the form of acomplex, as desired. It is also possible to produce metal complexes thatcombine the two active ingredients I and II with one another to form amixed complex.

Metal complexes comprise the basic organic molecule and an inorganic ororganic metal salt, for example the halides, nitrates, sulfates,phosphates, acetates, trifluoroacetates, trichloroacetates, propionates,tartrates, sulfonates, salicylates, benzoates etc. of the elements ofthe second main group, such as calcium and magnesium, and of the thirdand fourth main groups, such as aluminium, tin or lead, and also of thefirst to eighth sub-groups, such as chromium, manganese, iron, cobalt,nickel, copper, zinc, etc.. The sub-group elements of the 4th period arepreferred. The metals may be present in any of their various valencies.The metal complexes may be mononuclear or polynuclear, that is to say,they may contain one or more organic molecules as ligands, as, forexample, in the case of the above-mentioned mixed complexes of triazolecomponent I and anilino-pyrimidine II.

The triazole components I may be in stereoisomeric form or in the formof racemates. While components IC and IG to IJ can form twostereoisomers, four stereoisomers are possible for each of the othercomponents IA (propiconazol), IB (difenoconazol), ID (triadimenol), IE(BAS-480-F) and IF (cyproconazol). The various stereoisomeric forms ofthe compounds may have different fungicidal actions. For example, in thecase of propiconazol, the two cis-isomers are preferred, that is to say,those enantiomers in which the triazolylmethyl group and the propylgroup are on the same side of the dioxolane ring. In the case ofBAS-480-F, the two Z=cis)-isomers are preferred.

In practice, the active ingredients I and II can advantageously be usedin the form of free bases and in the form of racemates, to which theremay also be added other agrochemical active substances, such asinsecticides, acaricides, nematicides, herbicides, growth-regulators andfertilisers, but especially other microbicides.

In recent years so-called ergosterol-biosynthesis inhibitors have beenintroduced onto the market to a greater extent, that is to say,compositions of which the fungicidal action is based on preventing thebiosynthesis of the ergosterol occurring in the cell membrane of fungi.Fungicides that contain a 1H-1,2,4-triazole radical in the moleculegenerally act as 14-C demethylation inhibitors (=DMI) during thisprocess. The use over many years of compositions based on triazoles has,however, in some cases already led to the development of fungal strainsthat have demonstrably reduced sensitivity.

It has surprisingly now been found that mixtures of any triazolefungicides, and especially those of components I, and theanilinopyrimidine II, exhibit in their fungicidal action not onlyadditive action but also distinct synergistically enhanced action, evenin the case of fungus isolates that have acquired reduced sensitivity totriazole fungicides.

The present invention accordingly constitutes a very considerableenrichment of the art.

In addition to covering the two-component mixture, the present inventionrelates also to a method of controlling fungi, which comprises treatinga site that has been infested with fungi or is in danger of being soinfested, in any sequence or simultaneously, with a) one of thecomponents I or a (metal) salt thereof and with b) the active ingredientof formula II or a (metal) salt thereof, it also being possible for thechoice of salts to be such that the two active ingredients are bonded toone acid radical or, in the case of a metal complex, to one centralmetal cation.

Favourable ratios of the two active ingredients are I:II=7:1 to 1:30,preferably I:II=4:1 to 1:10. In many cases, mixtures in which the ratioof the pure active substances I:II=1:2 to 1:10, for example 1:3, 1:5, or1:8, are advantageous.

The active ingredient mixtures I+II according to the invention possessvery advantageous curative, preventive and systemic fungicidalproperties for the protection of cultivated plants. With the presentactive ingredient mixtures, it is possible to inhibit or destroy themicroorganisms occurring in plants or in parts of plants (fruit,blossoms, leaves, stems, tubers, roots) in different crops of usefulplants, while at the same time the parts of plants which grow later arealso protected from attack by such microorganisms. This appliesespecially also to microorganisms that have developed reducedsensitivity to fungicides of the triazole class.

The active ingredient mixtures are effective against the phytopathogenicfungi belonging to the following classes:

Ascomycetes (for example Venturia, Podosphaera, Erysiphe, Monilinia,Uncinula); Basidiomycetes (for example the genera Hemileia, Rhizocconia,Puccinia); Fungi imperfecti (for example Botrytis, Helminthosporium,Rhynchosporium, Fusarium, Septoria, Cercospora, Alternaria, Pyriculariaand especially Pseudocercosporella herpotrichoides). The activeingredient mixtures have systemic action. They can also be used asdressing agents for protecting seeds (fruit, tubers, grains) and plantcuttings against fungus infections as well as against phytopathogenicfungi occurring in the soil. The active ingredient mixtures according tothe invention are distinguished by the fact that they are especiallywell tolerated by plants and are environmentally friendly.

Target crops for the areas of indication disclosed herein are, withinthe scope of this invention, for example, the following plant species:cereals: (wheat, barley, rye, oats, rice, sorghum and related crops);beet: (sugar beet and fodder beet); pomes, drupes and soft fruit:(apples, pears, plums, peaches, almonds, cherries, strawberries,raspberries and blackberries); leguminous plants: (beans, lentils, peas,soybeans); oil plants: (rape, mustard, poppy, olives, sunflowers,coconut, castor oil plants, cocoa beans, groundnuts); cucumber plants:(cucumber, marrows, melons); fibre plants: (cotton, flax, hemp, jute);citrus fruit: (oranges, lemons, grapefruit, mandarins); vegetables:(spinach, lettuce, asparagus, cabbages, carrots, onions, tomatoes,potatoes, paprika); lauraceae: (avocado, cinnamon, camphor) or plantssuch as maize, tobacco, nuts, coffee, sugar cane, tea, vines, hops,bananas and natural rubber plants, as well as ornamentals (flowers,shrubs, deciduous trees and conifers). This list does not constitute alimitation.

The active ingredient mixtures of formulae I and II are normally appliedin the form of compositions. The active ingredients of formula I and theactive ingredient of formula II can be applied to the crop area or plantto be treated simultaneously or, alternatively, in succession on thesame day, if desired together with further carriers, surfactants orother application-promoting additives customarily employed informulation technology.

Suitable carriers and additives can be solid or liquid and correspond tothe substances ordinarily employed in formulation technology, e.g.natural or regenerated mineral substances, solvents, dispersants,wetting agents, tackifiers, thickeners, binders or fertilisers.

A preferred method of applying an active ingredient mixture thatcomprises at least one of each of those active ingredients I and II isapplication to the parts of plants above the ground, especially theleaves (foliar application). The number of applications and the rate ofapplication depend on the biological and climatic living conditions ofthe pathogen. However, the compounds can also penetrate the plantthrough the roots via the soil (systemic action) if the locus of theplant is impregnated with a liquid formulation, or if the compounds areapplied in solid form to the soil, e.g. in granular form (soilapplication). The compounds of formulae I and II can also be applied toseeds (coating) either by impregnating the seeds in succession with aliquid formulation of a compound or by coating them with an alreadycombined moist or dry formulation. Furthermore, in special cases, othertypes of application to plants are possible, e.g. the selectivetreatment of the buds or the infructescence.

The compounds of the combination are used in unmodified form orpreferably together with the adjuvants conventionally employed informulation technology, and are therefore formulated in known manner,e.g. into emulsifiable concentrates, coatable pastes, directly sprayableor dilutable solutions, dilute emulsions, wettable powders, solublepowders, dusts, granules, and also encapsulations in e.g. polymersubstances. As with the nature of the compositions, the methods ofapplication, such as spraying, atomising, dusting, scattering, coatingor pouring, are chosen in accordance with the intended objectives andthe prevailing circumstances. Advantageous rates of application of theactive ingredient mixture are generally from 150 g to 3 kg a.i./ha,especially from 200 g to 2 kg a.i./ha, especially preferably from 400 gto 1.5 kg a.i./ha.

The formulations are prepared in known manner, e.g. by homogeneouslymixing and/or grinding the active ingredients with extenders, e.g.solvents, solid carriers and, where appropriate, surface-activecompounds (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably the fractionscontaining 8 to 12 carbon atoms, e.g. xylene mixtures or substitutednaphthalenes, phthalates such as dibutyl phthalate or dioctyl phthalate,aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols andglycols and their ethers and esters, such as ethanol, ethylene glycol,ethylene glycol monomethyl or monoethyl ether, ketones such ascyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone,dimethyl sulfoxide or dimethylformamide, as well as vegetable oils orepoxidised vegetable oils, such as epoxidised coconut oil or soybeanoil; or water.

The solid carriers used e.g. for dusts and dispersible powders, arenormally natural mineral fillers such as calcite, talcum, kaolin,montmorillonite or attapulgite. In order to improve the physicalproperties it is also possible to add highly dispersed silicic acid orhighly dispersed absorbent polymers. Suitable granulated adsorptivecarriers are porous types, for example pumice, broken brick, sepioliteor bentonite; and suitable nonsorbent carriers are, for example, calciteor sand. In addition, a great number of pregranulated materials ofinorganic or organic nature can be used, e.g. especially dolomite orpulverised plant residues.

Depending on the nature of the compounds of formulae I and II to beformulated, suitable surface-active compounds are nonionic, cationicand/or anionic surfactants having good emulsifying, dispersing andwetting properties. The term "surfactants" will also be understood ascomprising mixtures of surfactants.

The surfactants customarily employed in formulation technology appear,inter alia, in the following publications:

"McCutcheon's Detergents and Emulsifiers Annual" MC Publishing Corp.,Glen Rock, N.J., 1988.

M. and J. Ash, "Encyclopedia of Surfactants", Vol. I-III, ChemicalPublishing Co., New York, 1980-1981.

Especially advantageous, application-promoting additives are alsonatural or synthetic phospholipids from the series of the cephalins andlecithins, e.g. phosphatidylethanol-amine, phosphatidylserine,phosphatidylglycerol and lysolecithin.

The agrochemical compositions generally comprise 0.1 to 99%, especially0.1 to 95%, of compounds of formulae I and II, 99.9 to 1%, especially99.9 to 5%, of a solid or liquid adjuvant and 0 to 25%, especially 0.1to 25%, of a surfactant.

Whereas commercial products will preferably be formulated asconcentrates, the end user will normally employ dilute formulations.

The present invention relates also to such (agro)chemical compositions.

The following Examples serve to illustrate the invention, the term"active ingredient" denoting a mixture of compound I and compound II ina specific ratio.

    ______________________________________                                        Wettable powders     a)       b)     c)                                       ______________________________________                                        active ingredient    25%      50%    75%                                       I:II = 1:3(a), 1:5(b), 1:8(c)!                                               sodium lignosulfonate                                                                              5%        5%    --                                       sodium lauryl sulfate                                                                              3%       --      5%                                      sodium diisobutylnaphthalenesulfonate                                                              --        6%    10%                                      octylphenol polyethylene glycol ether                                                              --        2%    --                                       (7-8 mol of ethylene oxide)                                                   highly dispersed silicic acid                                                                      5%       10%    10%                                      kaolin               62%      27%    --                                       ______________________________________                                    

The active ingredient is thoroughly mixed with the adjuvants and themixture is thoroughly ground in a suitable mill, affording wettablepowders which can be diluted with water to give suspensions of thedesired concentration.

    ______________________________________                                        Emulsifiable concentrate                                                      ______________________________________                                        active ingredient (I:II = 2:5)                                                                          10%                                                 octylphenol polyethylene glycol ether                                                                    3%                                                 (4-5 mol of ethylene oxide)                                                   calcium dodecylbenzenesulfonate                                                                          3%                                                 castor oil polyglycol ether (35 mol                                                                      4%                                                 of ethylene oxide)                                                            cyclohexanone             30%                                                 xylene mixture            50%                                                 ______________________________________                                    

Emulsions of any required dilution, which can be used in cropprotection, can be obtained from this concentrate by dilution withwater.

    ______________________________________                                        Dusts             a)        b)     c)                                         ______________________________________                                        active ingredient  I:II = 1:5 (a);                                                               5%        6%     4%                                        5:7 (b) and 1:2 (c)!                                                          talcum            95%       --     --                                         kaolin            --        94%    --                                         mineral filler    --        --     96%                                        ______________________________________                                    

Ready-for-use dusts are obtained by mixing the active ingredient withthe carrier and grinding the mixture in a suitable mill. Such powderscan also be used as a dry dressing for seed.

    ______________________________________                                        Extruder granules                                                             ______________________________________                                        active ingredient (I:II = 2:3)                                                                         15%                                                  sodium lignosulfonate     2%                                                  carboxymethylcellulose    1%                                                  kaolin                   82%                                                  ______________________________________                                    

The active ingredient is mixed and ground with the adjuvants, and themixture is subsequently moistened with water. The mixture is extrudedand then dried in a stream of air.

    ______________________________________                                        Coated granules                                                               ______________________________________                                        active ingredient (I:II = 2:5)                                                                     8%                                                       polyethylene glycol (mol. wt. 200)                                                                 3%                                                       kaolin               89%                                                      ______________________________________                                         (mol. wt. = molecular weight)                                            

The finely ground active ingredient is uniformly applied, in a mixer, tothe kaolin moistened with polyethylene glycol. Non-dusty coated granulesare obtained in this manner.

    ______________________________________                                        Suspension concentrate                                                        ______________________________________                                        active ingredient (I:II = 2:7)                                                                          36%                                                 propylene glycol          10%                                                 nonylphenol polyethylene glycol ether                                                                   10%                                                 (15 mol of ethylene oxide)                                                    sodium lignosulfonate     10%                                                 carboxymethylcellulose     1%                                                 silicone oil (in the form of a 75%                                                                       1%                                                 aqueous emulsion)                                                             water                     32%                                                 ______________________________________                                    

The finely ground active ingredient is intimately mixed with theadjuvants, giving a suspension concentrate from which suspensions of anydesired dilution can be obtained by dilution with water. Using suchdilutions it is possible to treat living plants and also plantpropagation material by spraying, watering or impregnation and toprotect them from attack by microorganisms.

BIOLOGICAL EXAMPLES

A synergistic effect always exists in the case of fungicides when thefungicidal action of the active ingredient combination is greater thanthe sum of the action of the active ingredients applied individually.

The expected action E for a given combination of active ingredients, forexample two fungicides, obeys the so-called COLBY formula and can becalculated as follows (COLBY, L. R. "Calculating synergistic andantagonistic responses of herbicide combination". Weeds 15, pages20-22.2) (LIMPEL et al., 1062 "Weed control by . . . certaincombinations". Proc. NEWCL, Vol. 16, pp. 48-53):

(g a.i./ha=gram active ingredient per hectare)

X=% action by fungicide I at p g a.i./ha

Y=% action by fungicide II at q g a.i./ha

E=the expected action of fungicides I+II at a rate of application of p+qg a.i./ha (additive action),

thus, according to Colby:

    E=X+Y-(X·Y)/100

If the action actually observed (O) is greater than the expected action,then the action of the combination is super-additive, that is to say, asynergistic effect exists.

Action against "powdery mildew" on winter wheat

Method:

In a greenhouse, approximately 20 plants of the winter wheat variety"Bernina" are grown in pots 16 cm in diameter at 20° C. and 60% relativehumidity for 12 hours during the daytime and at 16° C. and 80% relativehumidity during the night. When side-shoots start to form (EC 21), theplants are inoculated with an isolate of Erysiphe graminis f.sp. triticithat exhibits a reduced sensitivity to DMI fungicides.

3 days after the inoculation, the individual active ingredient or thefungicidal mixture is applied in the form of an aqueous suspension usinga spray bar under field conditions at a rate of application of water of500 I/ha. 4 days and 11 days after application the change in theinfestation on the leaf surface present at the time of inoculation isdetermined (evaluation of primary infestation). 3 replicates are carriedout for each test.

At various ratios of one of the components IA to IK and component II, asynergistically enhanced fungicidal action occurs.

Such enhancement of action is achieved not only against powdery mildewspecies but also against rust and scab diseases, stem-break, leaf blotch(for example Septoria or species of net blotch), grey mould rot andother pathogens.

Preferred ratios (in amounts by weight) are:

    ______________________________________                                        IA:II =   5:1 to 1:30  IF:II = 5:1 to 1:20                                    IB:II =   3:1 to 1:11  IG:II = 3:1 to 1:12                                    IC:II =   3:1 to 1:8   IH:II = 3:1 to 1:15                                    ID:II =   7:1 to 1:12  IJ:II = 5:1 to 1:24                                    IE:II =   4:1 to 1:30  IK:II = 2:1 to 1:14.                                   ______________________________________                                    

What is claimed is:
 1. A fungicidal composition containing asynergistically effective amount of a mixture of4-(4-chlorophenyl)-2-phenyl-2-(1,2,4-triazol-1-ylmethyl)butyronitrile ora salt or metal complex thereof as component I and4,6-dimethyl-N-phenyl-2-pyrimidinamine of the formula ##STR2## or a saltor metal complex thereof as component II, and an inert carrier therefor,wherein the ratio by weight of component I to component II is in therange of about 7:1 to 1:10.
 2. A composition of claim 1, wherein theratio of I:II is 4:1 to 1:10.
 3. A composition of claim 2, wherein theratio of I:II is 1:2 to 1:10.
 4. A method of controlling fungi or ofpreventing fungus infestation, which comprises applying to 1) a part ofthe plant that has been infested with fungi or is in danger of being soinfested or 2) a locus of the plant's growth in any sequence orsimultaneously a synergistically effective amount of4-(4-chlorophenyl-2-phenyl-2-(1,2,4-triazol-1-ylmethyl)-butyronitrile ora salt or metal complex thereof as component I and4,6-dimethyl-N-phenyl-2-pyrimidinamine of the formula ##STR3## or a saltor metal complex thereof as component II, wherein the ratio by weight ofcomponent I to compound II is in the range of about 7:1 to 1:10.
 5. Amethod of claim 4 wherein the ratio I:II is 4:1 to 1:10.
 6. A method ofclaim 4 wherein the ratio I:II is 1:2 to 1:10.
 7. A method of claim 4,wherein the seed is treated.